The present application relates to systems, apparatuses and methods including a lifting device for transporting disk stacks, such as removable cell-type filters through which fluids are passed for filtration, more particularly, to systems, apparatuses and methods including a lifting device for easily, safely and effectively transporting disk stacks, such as removable cell-type filter cartridges, during the removal of the cartridge or cartridges from a removable cell-type filter cartridge assembly and, most particularly, to an adjustable lifting device for easily, safely and effectively installing and removing disk stacks, such as cell-type filter cartridges, from a removable filter cartridge housing.
Cell-type filter cartridges have long been known and have been increasingly used in a variety of filtration situations. These types of filter cartridges are typically fabricated from individual cells generally having two layers of filter media separated from each other. Liquid typically flows from the outside of the filter medium into the space between the layers of the filter media toward the central portion of the cell. A significant advantage to cell-type filter cartridges is that the surface area of filter material is quite large when compared to the total volume of an assembled cell-type filter cartridge.
Disposed between each filter medium is a separator which is typically formed in the shape of disks having ribs radially extending from the central aperture in a spoke-like pattern. In addition to separating the two layers of filter media, it provides for fluid flow from the filter media toward the central aperture of the filter media.
The separator disk conventionally has stiffening members formed at the central aperture of the cell which are attached to a plurality of separating ribs to provide a rigid, box-like structure sufficient to impart substantial cantilever strength to the ribs. Further, one of the stiffening disks is conventionally positioned proximate the ends of the separator ribs in order to act as a loadbearing surface to prevent media intrusion of the filtering medium and to prevent blocking the area of the flow path with the filtered liquid. Accordingly, one distinct advantage in this type of separator is that during backwashing or reverse flow (i.e., fluid flow from the central aperture of the filter cell out toward the surface of the filter medium) damage to the filter media is minimized.
Filter cartridges use a variety of filter media for filtering many fluids. Examples of such media and uses may be found, for example, in U.S. Pat. No. 4,617,128 "Particulate Filter Aid, Filter Bed Process" dated Oct. 14, 1986, to Ostreicher; U.S. Pat. No. 4,309,247 "Filter and Method of Making Same" dated Jan. 5, 1982, to Hou et al.; U.S. Pat. No. 4,305,782 "Filter and Method of Making Same" dated Dec. 15, 1981, to Ostreicher et al.; U.S. Pat. No. 4,007,113 "Particulate Filter Medium and Process" dated Feb. 8, 1977, to Ostreicher; and U.S. Pat. No. 4,007,114 "Fibrous Filter Medium and Process" dated Feb. 8, 1977, to Ostreicher. All of the foregoing patents are incorporated herein by reference.
Use of a cell-type filter cartridge may be also found in U.S. Pat. No. 4,361,486 "Filter Media, Method for Oxidizing and Removing Soluble Iron, Method for Removing Inactivating Microorganisms and Particulate Filter Aid" issued Nov. 30, 1982, to Hou et al. which is incorporated herein by reference.
A process for manufacturing filter cells is described in U.S. Pat. No. 4,347,208 "Method of Making Filter Cell Having Sealed Periphery" issued Aug. 31, 1982, to Southall, the disclosure of which is herein incorporated by reference. In this patent, a filter cell cartridge is described which comprises a plurality of filter cells. Each of the filter cells is comprised of filter media having a conical separator therebetween with the periphery or edges of the filter cell being held together and sealed by an injection-molded flange.
A method for disposing a netting or mesh on the outside of the filter material is disclosed in U.S. Pat. No. 4,881,313 "Method of Forming a Cell Filter With an Exposed Surface" issued to Artinyan et al., the disclosure of which is herein incorporated by reference. In this patent, the surface area of filter exposed to unfiltered fluid has disposed thereon a netting thereby preventing flaking, cracking and the like of filter media during backflow or cleaning operations. The netting is secured to the cell by a molded circumferential retainer and a circumferential centrally disposed ring.
Generally, all of the aforementioned filter cartridges perform as anticipated during normal operating conditions. As can be expected after extended use, the filtering capacity of the filter media diminishes accordingly. Once the filter performance has diminished, the filter cartridges are typically replaced by grasping the periphery or edge of the uppermost filter cell, and then carefully lifting the attached filters away from the filter housing. This method relies on the strength of the individual wet cells, as well as that of the bands which interconnect the multiple filter cells, to prevent any one of the attached filter cells from breaking apart. Alternatively, if the construction of the filter housing permits, the bottom filter may be grasped around its periphery and then removed by carefully lifting the cartridge up and out of the filter housing. Both of the aforementioned methods are problematic because of the increased weight of a wet filter cartridge as compared to the weight of a dry filter cartridge. This increased load is generally concentrated toward the center of the cartridge, thus resulting in the likelihood of the cartridge separating during the lifting operation.
A wet filter cartridge that breaks during removal from a filter housing causes several problems. Primarily, if the cartridge breaks while still in the vicinity of the housing, the particulate matter removed by the filters may re-enter the housing, thus requiring additional cleaning operations in and around the housing.
It is known to provide handles for lifting and carrying bulky items such as filter cartridge assemblies including handles operatively disposed on the filter cell cartridge, as disclosed in U.S. Pat. No. 5,607,584 assigned to the assignee of the present application, the disclosure of which is hereby incorporated by reference. However, the prior art does not provide means for removing a filter cartridge from a location, after removal of the filter cartridge housing, without an operator physically lifting the filter cartridge from its operating position and manually transporting the filter cartridge to a location removed from the operating position. Because the manual removal of the cartridge from the operating position often involves the use of stairs by an operator while transporting the heavy cartridge, as well as possibly contacting toxic substances on the exterior portion of the filter cartridges, systems including a lifting device and methods of using the lifting device that would eliminate the need for an operator to manually transport the cell-type filter cartridges and to reduce the overall time needed to remove and replace the cell-type filter cartridges is desirable
Thus, there is a need for systems, including a lifting device, and methods for easily, safely and effectively removing used disk stacks, such as cell-type filter cartridges, used in filtration operations from their operative position in housings after the housing enclosure has been removed. Such systems and methods should avoid manual lifting and transporting of the disk stacks. Such systems and methods should eliminate or at least minimize direct contact between operators and the cell-type filter disks in order to minimize operator contact with possible dangerous or toxic substances and minimum contaminating the environment of the filter housing with slippery, toxic or dangerous material that may have been collected on the outer surfaces of the cell-type filter disk. Such systems and methods should eliminate or endeavor to minimize any heavy lifting required by an operator, thereby contributing to a safer operating environment. Such systems and methods should endeavor to reduce the overall time required to change cell-type filter cartridges and thereby reduce the downtime attributable thereto. Such systems and methods should eliminate the requirement for operators to manually transport or move the cell-type filter disk up or down stairs. Such systems and methods should provide for cleaner, less contaminated filter surfaces when new replacement cell-type filter cartridges are positioned in filter housings. Such systems and methods should facilitate the placement of the used cell-type filter cartridges in waste enclosures.